(a) Field of the Invention
The present invention relates to an electronic blackboard (hereinafter “board”), more particularly, to an electronic board that comprises a polarizing film comprising a plastic film with high hardness that may replace a cover plate.
This application is a National Stage Entry of International Application No. PCT/KR2015/001662, filed on Feb. 17, 2015, and claims the benefit of and priority to Korean Application No. 10-2014-0020288, filed on Feb. 21, 2014 and Korean Patent Application No. 10-2015-0024301, filed on Feb. 17, 2015, all of which are incorporated herein by reference in their entirety for all purposes as if fully set forth herein.
(b) Description of the Related Art
A display device is a device that treats an image data input from the outside or an image data stored inside by various processes and displays as an image on a display panel or screen, and it may be variously realized in the form of a TV, a monitor, a portable media player and the like according to the purpose. With the development of technology, various functions are added and reinforced to the display device, and for example, it may be realized in the form of an electronic board.
An electronic board is a board capable of interactively communicating with a computer, such as signalizing written contents contacted on the surface of a display device to directly realize as an image on the display device, and is currently developed in various forms.
In the case of a thin display device such as a liquid crystal display device or an organic electroluminescent device generally used in an electronic board, a cover plate consisting of glass or tempered glass is installed on the surface so as to protect a display from external impact or scratch and the like, and recently, with the rapid development of devices including a touch function such as a smart phone or a tablet PC, standards for durability and abrasion resistance required for a display device is increasingly rising.
However, in the case of a cover plate made of glass material that was generally used in an electronic board in the prior art, since the weight and the thickness are significant, it is not suitable for a thinning and weight-lightening tendency, and it has a problem of being easily broken by external impact.
Thus, ways to replace a cover plate using plastic resin that is easy to make weight-light and infrangible are being studied. However, in order to improve hardness of a plastic film to a level capable of replacing glass, the thickness of a resin layer should be above a certain thickness, for example, 50 μm, or 70 μm, or 100 μm, but a plastic resin layer has problems in that curl or bending due to cure shrinkage may be easily generated as the thickness increases, and cracks may be generated with the curing of the resin layer.
Accordingly, there is a need for development of technology capable of weight-lightening and thinning a device while affording excellent durability and abrasion resistance so as to realize a touch function in a large scale display such as an electronic board and the like.